SET IN STONE: The Brooklyn Museum will auction salvaged sculptures and building facades.Ben Parker

The Brooklyn Museum is planning to auction off a significant slice of the Big Apple’s past — a magnificent collection of terracotta facades and late-Victorian stone ornaments saved from buildings razed between the 1950s and 1970s.

“There’s nothing else like it in America,” said Karp, best known for helping discover Andy Warhol.

He said that Arnold Lehman, the museum’s director, assured him in 2007 that he’d get back any pieces the institution no longer wanted.

But Karp said he recently learned from a reporter for The Atlantic magazine that the museum wants to sell much of the collection.

Among the treasures Karp helped save over the years are a now-century-old roaring zinc lion from the old El Dorado carousel in Coney Island.

The museum didn’t deny the magazine’s report, but said it “currently has no agreement with any sales venue” regarding the artifacts.

“They should have given me the first chance to buy,” said Karp, who in 1985 opened a small museum upstate in Charlottesville that displays about 150 such pieces.

It was roughly 60 years ago when Karp and a few friends started making arrangements with construction crews and the city to salvage objects facing wrecking balls. They sometimes even used the scaffolding themselves to scale high rises and collect items of artistic value.

Karp eventually approached the museum and worked out a deal to donate about 400 pieces.

In 1966 it built a sculpture garden to display about 200 of them. The collection grew substantially over the years to become a public destination.

In 2004, the garden was cut back to 62 objects, with 275 others left in limbo behind the parking lot, The Atlantic said.